Optical properties of Ta2O5 thin films deposited by plasma ion-assisted deposition

초록

In this study Ta2O5 films were deposited by plasma ion-assisted deposition (PIAD) and conventional evaporation (CE) and the optical and structural properties of them were investigated. The result shows that refractive index of Ta2O5 film deposited by PIAD with substrate heating at T=150 oC is the highest. Ta2O5 films deposited by PIAD tend to show higher refractive index and smoother surface roughness than those by CE regardless of substrate heating. Optical multilayer filters with Ta2O5 and SiO2 films were deposited by PIAD and CE, respectively, and the spectral shift of a PIAD filter is less than of a CE filter. It suggests that the PIAD method combined with substrate heating leads to denser microstructure and smoother surface of Ta2O5 films due to an increase in mobility of arrival particles assisted by Ar ion bombardment and thermal energy